(I had no idea I hadnâ€™t done two out of the three required quests in order to do this one when I signed up for it. Oh, well. More Quest Points)
The quests needed for this one are The Creature of Fenkenstrain, Cabin Fever, and the Pirate Pete portion of Recipe for Disaster.
Speak with Brother Tranquility on Mos Leâ€™Harmless to begin. He will then teleport you to Harmony Isle. When you arrive, to your surprise, some of the monks are zombies! Hereâ€™s where you come in. Run out to the courtyard and push away the Saradomin statue to reveal a cave.
Once in you have to equip your breathing equipment and submerge into the watery depths. Make your way to the end of the chasm and repair the steps, then make your way up and into a secret room. Gaze through the peephole. You will hear the pirates are scheming with poison gas.
Return to Brother Tranquility by heading back down the watery hallway. Tell him of the piratesâ€™ plan. He will tell you to go to the Monastery just west of Edgeville and get the Prayer book from the north-eastern bookcase. One you have that and are back in the granary, recite the prayer. That will protect the granary from the gas.
Now you have to go to Dr. Fenkenstrain and get him to perform brain surgery on the monks. In order to get him to Harmony Isle, though, you have to smuggle him out. After talking to him and devising a plan, talk to Rufus, the meat seller, in Canifis. He’ll think you are smuggling cats instead of mad doctors and give you a whistle and some crate parts. With at least 20 nails and 4 planks, return to Fenkenstrain and you’ll find a crate hotspot like you’d see in your house and build the crate. Then create 10 cats by planks and regular fur at your own workbench or someone elses. Once that’s done, put all the cats int he crate and blow the whistle, and Rufus will take it away.
Once back at the granary, go downstairs. Fenkenstrain will list out the tools he needs, and you will have to go get them. Blow up the door on the monastery with a gunpowder bomb and fuse you find on the crashed ship nearby and kill the zombie pirate surgeon things until you have all of the tools. Now head back to Fenkenstrain and he will perform the surgery.
Now return to where you were killing the pirates for the tools and speak with Mi-Gor. He will release his monster on you, the level 190 Barrelchest. This thing hits hard and often so make sure you have good armor and lots of food or youâ€™re in trouble.
Once you defeat the monster, speak with Brother Tranquility. Congratulations, quest complete.
Broken Barrelchest Anchor (can be repaired for 230k and used as a weapon)
6k Prayer XP
2k Construction XP
3k Crafting XP